I'm not sure if this is a problem or simply normal operation, but many of my Nelson heads throw water at two levels - a high stream that reaches pretty far, and a lower stream that sprays nearer to the head. Problem is when I bank the radius down with the screw, I still get overspray with the far reaching stream. I reacently added some Hunter I-20's bought at Sprinkler Warehouse (thanks!) and they seem to function much better.